Hybrid Sunlight > IBL

[podperson]

Hybrid Sunlight > IBL

It would be great if sunlight could essentially work by generating an HDRI texture dynamically (and possibly caching it). Why?

1. AO/Radiosity renders faster in a lot of cases
2. You get even more realistic shadows
3. You can then generate some kind of backdrop / reflection map (sure it won't be very interesting, but it's better than nothing)

If you could export the resulting HDRs as panoramas or probes and then edit them that would be nice too.

 

[ROI]

Isn't this sort of what happens if you click the 'Geometry' option on the sunlight? You get a blue sky with a sun (even haze, with turbidity cranked up), shadows, reflections etc - all rendering fairly speedily with AO.

Of course, if Martin could also simulate clouds and weather...:wink:

 

[frank beckmann]

Just an addition.

With kindest regards
Frank

Just a side note: While rendering the skylight panorama the intensity setting won´t effect the output.

 

[podperson]

Ah I missed that

Not sure why the checkbox is labelled "Geometry"...

Oh -- and what if I want reflections but no background?

And -- how did you render the panorama Frank?

I might also add that skylight + AO is WAAAAAY slower than a simple HDRI + AO and the sun does not look very convincing.

The first image rendered much quicker. HDR image + AO.

The second image rendered so slowly I thought C3D had hung. Skylight (geometry checked) + AO.

 

[frank beckmann]

Hi.
Check this:

 

[DaVinci]

And -- how did you render the panorama Frank?

Dunno, but what about texture baking a sphere with 100% reflection material?
Though you would then need a smart way to relax the UV and stretch it to a rectangle.

 

[ROI]

@podperson

I might also add that skylight + AO is WAAAAAY slower

Try reducing the 'Samples' property of the skylight to 1... seems to speed things up without affecting the quality.

(I don't know why this works but it does.)

 

[ROI]

@Frank

Very clever of you to render the empty sky, but how do you save the panorama as an HDRI image with the full range of illumination values?

 

[podperson]

I'm guessing saving as .hdr just works? Edit: nope, tried that.

However, the sun still doesn't look right (in the rendered sky, or in the renders -- although it looks better in your render (using the rendered panorama) than in mine (using the sunlight).

Here's a rendered sky geometry contrasted with a bryce sky panorama.

 

[frank beckmann]

@Frank

Very clever of you to render the empty sky, but how do you save the panorama as an HDRI image with the full range of illumination values?

I'm guessing saving as .hdr just works? Edit: nope, tried that.

Hi.
As discribed; Make sure to cache the hdri by check the render preferences. Render and save as "yxz.hdr". No cached hdri = no saving to ".hdr". Simple heh?

With kindest regards
Frank

 

[frank beckmann]

Hi.
Here´s a Bryce sky panorama tiff rendered attached to the Cheetah3d hdri tag. Not too bad for a tiff I think

Frank